Wednesday, October 4, 2023

Some notes on the soils in the vegetable landscape of Benguet, Northern Luzon

Soils are formed from the weathering of rocks as influenced by climate, parent rock, topography, living organisms, and time. Among these factors, climate and topography appear to be the dominant factors that have influenced the properties and distribution of soils in Benguet, Northern Luzon. 

Benguet together with Abra, Apayao, Baguio City, Ifugao, Kalinga, and Mountain Province comprise the Cordillera Administrative Region (CAR). Benguet has a mountainous topography consisting of peaks, ridges, and canyons ranging in elevation from about 900m to 2,840m above sea level. 

The highest point of the Philippine highway in Cattubo, Atok, Beneguet

The subtropical highland climate (Cwb based on K√∂ppen climate classification) with annual average highs of 25.3 °C in April and lows of 13.3 °C in January and an average precipitation of 1,829mm (Wikipedia) promotes moderate rock weathering and soil formation rates. The steep slopes on most mountain sides enhances rapid leaching and runoff, the latter results in severe soil erosion on cultivated and bare slopes. 

Steep slopes with young soils are terraced and planted to various vegetables
Most soils in Benguet have developed from diorite, an intermediate plutonic rock, as well as metavolcanics and metasedimentary rocks particularly slate. According to the published literature, the dominant natural vegetation of Benguet was the pine forest type. Compared with broadleaf forests, pine forests have lower soil organic carbon (SOC) contents, smaller labile carbon fractions, and lower amounts of SOC stocks. Moreover, pine forests tend to experience severe water erosion events (Nie et al., 2019. Catena 174: 104-111).

Outcrops of metasedimentary rocks in Atok, Benguet

The high soil erosion rates result in poorly developed and thin soils (Inceptisols). On more stable surfaces such as on summit positions, old soils can be found which may qualify as Ultisols. Regardless of the stage of soil development, most soils are acidic with pH below 5.0 (Laurean et al., 2015. Benguet State University Research Journal 74: 10-34).

Red and old soils on summit positions in the mountains.

Where intensive vegetable production is found, the landscape can be called Anthropocene landscapes due to the considerable soil and landscape modification resulting from human activities such as land use conversion from forest to agriculture, terracing, fertilizer and pesticide application, liming and others.

The beautiful Anthropocene vegetable landscape in Natubling, Buguias, Benguet.

In general, the rates of fertilizer and lime application by the vegetable farmers are not based on recommended rates. This necessitates soil fertility assessment of vegetable farms to be able to determine the appropriate rates of fertilizer and lime application for improved vegetable production. This is one of the objectives of our ACIAR SlAM Project (2020117) on managing heavy metals and soil contaminants in vegetable production led by Dr. Steve Harper of the University of Queensland, Australia.

Our ACIAR Slam Project Team from the Univ Queensland, UPLB, BSU, VSU & USTP

Wednesday, April 20, 2022

What caused the Baybay landslides during the Tropical Depression Agaton on April 11, 2022?

The Baybay landslides on April 11, 2022, brought about by the Tropical Depression Agaton, have already claimed 116 lives, and many victims are still missing. Social media is buzzing with explanations about what caused the landslides. As usual, deforestation is claimed as the top culprit. And as always, the deforestation issue is politicized. But is it the cause of the landslides? Several factors cause landslides. In the case of the Baybay landslides, the most important are geology (rock type), topography (slope), soil characteristics, land use (and vegetation cover), and rainfall. Let me explain the role of each factor.


All the landslides in Baybay are located on the western slopes of the central highlands of Leyte, also called the Leyte Cordillera. This mountain range is volcanic, and the rocks consist mainly of pyroclastic rocks, specifically basalt and andesite. Pyroclastic rocks are fragmented or unconsolidated rocks produced by volcanic eruptions. Consequently, the slopes underlain by these materials are generally weak and prone to slope failure. This situation is aggravated by the presence of the Philippine fault line along the central highlands, which has caused the shearing of the rocks.

The common type of pyroclastic rocks in the central highlands of Leyte


The western slope of the central highlands is generally rugged and mountainous. The steepness of a mountain slope is a major determining factor in whether the slope will fail or not. The steeper the slope, the less stable it is. In the presence of a triggering factor such as a heavy rainfall event, steep slopes (>25%) may fail, thereby causing landslides. From the topographic maps available on the internet, one can easily see that the source areas of the Baybay landslides have steep slopes. 

Topographic maps show the steep slopes of the source areas
of Bunga & Kantagnos landslides


Soils vary in the stage of development from young (poorly weathered) in the plains to old (highly weathered) soils in the mountains. Young, very porous, and unstable volcanic soils (65% porosity) prone to land sliding are widespread in the upper mountain slopes, generally above 300 meters elevation, such as in Mailhi. Except for the Mailhi landslide, most of the Baybay landslides occurred on the old and highly weathered soils. These soils are highly friable, clayey, and prone to shallow landslides. When saturated with water, the clay serves as a lubricant for the sliding mixture of soil and rock debris. And also, regardless of soil type, the soil can turn into a liquid state when supersaturated with water resulting in mudslides.

The source area of the Bunga landslide with its highly weathered soil, deep-seated
characteristic, and mixed vegetation cover. (Photo Source: jbatravelvlog)

The source area of the deep-seated Kantagnos landslide with its highly weathered soil and relatively thick mixed vegetation. (Photo Source: Dan Michael Castanares)

The deep Mailhi landslide with its unstable young volcanic soil and mixed
vegetation cover. (Photo Source: jbatravelvlog)

Land use 

Vegetation cover, particularly trees, can prevent soil erosion and shallow landslides, which generally occurs within the root zone. No doubt, forest trees can minimize shallow landslides better than shallow-rooted plants like coconut and grasses like cogon. Studies have revealed that roots increase water permeability and the mechanical stability of shallow pyroclastic soil cover (Alfonso-Dias, 2019). Zhang et al. (2019) found that the 23-year-old reforest in the mountain in Tacloban, Leyte, positively affected the hillslope hydrological functioning. But deep landslides that occur below the root zone are beyond the control of the roots of the vegetation cover (Zhuang et al., 2022). In such a case, the failure of the land surface is controlled more by the steep slope and by the weak geological and soil foundation. This explains why landslides can occur under any type of vegetation cover or land use. For example, on a clear day, one can see several old landslide scars in the forest on Mt. Pangasugan. In the Bunga and Kantagnos landslides, the largest Baybay landslides, the source area in the upper part of the mountain is still covered with mixed vegetation consisting of trees and coconuts. And according to Forbes and Broadhead (2013), the forest cover will not affect the occurrence of landslides during extreme events such as heavy rainfall.


Excessive soil water content from heavy rainfall is generally considered the primary cause of slope failure (Forbes and Broadhead, 2013). The tremendous volume of rain dumped by Agaton in three days from April 9 to 11 was 907mm, which is one-third of the annual rainfall in Baybay (Source: VSU-PAGASA Agromet Station). This is close to a meter deep water poured into the land surface in Baybay in only 72 hours. This volume of water is equivalent to 9,000 cubic meters of water per hectare or 200 gallons per square meter. No vegetation type can absorb and evaporate this tremendous amount of water in so short a time. Likewise, no soil can either hold or percolate this volume of water in just 72 hours. Even the very porous young volcanic soil in Mailhi, which has an average porosity of 65% and moisture content at a field capacity of 40%, can only potentially absorb 58 gallons of water per square meter calculated to a depth of 1 meter. The old soil under the forest can potentially hold a maximum of only 61 gallons per square meter to a depth of 1 meter, while the old soil under coconut can hold only 55 gallons per square meter. These values are based on the assumption of a flat surface and fast infiltration rates which are not the case in the landslide areas. This means that the actual amount of water that the soils on the mountain slopes can hold is much lower than the values mentioned. As soon as the soil is saturated with water, the incoming rainwater cannot be accommodated in the soil pores and flows as surface runoff, causing the landslides and the flooding, for the first time in about four decades, the city center of Baybay. 

Severe flooding of the city center of Baybay due to Agaton on April 10, 2022.
This is the first severe flooding of Baybay that I have witnessed in
nearly four decades. (Photo Source: Discover Baybay City).


The Baybay landslides were triggered by the extremely heavy rainfall and enhanced by the unstable and highly weathered soils (or the young unstable volcanic soil in the case of Mailhi), weak geologic material composed of unconsolidated pyroclastic rocks, and the steep slopes. The role of vegetation cover is not straightforward since it can partly prevent shallow landslides but not deep-seated landslides such as those in Bunga, Kantagnos, and Mailhi. This means that the coconut's shallow root system (about a meter deep) may not have effectively prevented the landslides, but the same can be said of the trees with their 2-3 m deep rooting zone since the landslides are several meters deep in their source areas. Landslides are natural geologic processes on the land surface. Catastrophic landslides like those we have witnessed in Baybay may occur again anytime at any place with the above environmental conditions regardless of the vegetation cover. I suspect that several incipient landslides (landslides in the initial stage) were produced in various areas during Agaton but are hidden by the vegetation cover. Another typhoon may trigger these incipient landslides to become full or even catastrophic landslides. Thus, it is crucial that residents living in landslide-prone areas be given proper and timely advice. 


Alfonso-Dias 2019. Dissertation, University of Montpellier, France.

Forbes, K. and J. Broadhead. 2013. RAP Publication 2013/02. FAO Regional Office, Bangkok.

Zhang et al. 2019. Geoderma 333: 163-177.

Zhuang et al. 2022. Engineering Geology 298

Sunday, August 1, 2021

Are we biting the hand that feeds us? Knowing the Filipino farmer—their struggles and aspirations

by Lois Mauri Anne L. Liwanag
Bachelor of Science in Development Communication
Visayas State University

Waking up in the morning greeted by the inviting smell of freshly cooked rice for breakfast, drinking a bottle of cold buko juice on a warm summer afternoon, or coming home to a piping hot serving of sinigang loaded with fresh vegetables for dinner—these are only some of the many best things in life that most privileged Filipinos take for granted. 

Ironically enough, the persons who worked hard for the food served on dining tables are the very ones who are unable to eat a proper meal three times a day.   

Knowing the Filipino farmer

According to Asterio Saliot, the former director of the Department of Agriculture-Agricultural Training Institute (DA-ATI), the average age of a Filipino farmworker is 57, with an average level of education of grade five, working on an average of a 1.5-hectare farm. 

Their job is not limited to planting vegetables or fiber. They engage in agriculture which involves cultivating field or specialty crops, handling orchards or vineyards, and raising poultry or other livestock for food, fiber, and raw materials. The crops that they mainly focus on cultivating in the country include rice, corn, coconut, sugarcane, bananas, pineapple, coffee, mangoes, tobacco, and abaca. 

The said farmer receives less than half of the wage an average Filipino worker earns; they only produce one-sixth of the value of output produced by a worker in the industry. With lower wages and even much lower productivity, farmworkers make up two of every three of the country’s working poor (Habito, 2018). 

Farmers in the Philippines are generally poor and marginalized, unlike the ones in nations like the United States, China, Japan, and Thailand, where they are given more credit, resources, and most especially—respect.   

A rice farmer in Eastern Samar


Despite being in an agricultural country, Filipino farmers remain as one of the poorest sectors in the Philippines, with the highest poverty incidence in 2015 at 34.3 percent, according to the Philippine Statistics Authority (PSA). This ironic fact has been the reality of the people who feed the population and keep the economy alive.

At present, some farmers are said to believe that there is more money with education. In hopes of continuing under the agricultural sector, they send their young ones to school in order to gain more knowledge and skills. Unfortunately, the younger generations turn away from agriculture with their favor leaning towards livelihoods far from the hardship of being under the sun or soaking in dirt and mud. 

On the other hand, there are also some farmers who let their children help in the field as soon as they start to learn how to lift or till. As a result, there is a multitude of Filipino farmworkers who are not aware of the illegal or harmful farming practices they do because of inadequate proper education. They perform kaingin or slash-and-burn and apply excessive inorganic pesticides and fertilizers, thinking that these are the normal things to do since they have already grown used to it or they have already been doing this ever since. 

Apart from this, some of the common problems of the Filipino farmer that causes them to experience poverty, unproductivity, and marginalization are: 1) insufficient government support, 2) inequality in land distribution, 3) unfair trade practices, 4) increasing population growth, 5) natural calamities, 6) unpredictable market demand, and 7) armed conflicts specifically in Mindanao.   


The opportunity to interview some farmers and other agricultural workers arose at the Farmers’ and Fisherfolks’ Day held last April 27, 2019, as a part of the celebration of Visayas State University’s Anniversary. 

Several of them were asked one common question: Ano ang kaunlaran para sayo? [What is development for you?]

The said interview was supposedly a requirement for a project in a Development Communication course. However, it unexpectedly reflected some of the farmworkers’ vision and aspirations:

“Kaunlaran? Syempre pagsaka o pagtanim sa sariling lupa, sa Pilipinas.” 

[Development? Of course farming or planting on one’s land, in the Philippines.]

“’Yung hindi na natin kailangang humingi ng pananim ng ibang bansa.”

[When we no longer have to ask for the crops of other countries.]

“Para sa’kin, maunlad na siguro kung hindi na kailangan gumamit ng fertilizer at pesticide sa pagtanim.” 

[For me, it would have been better if there was no need to use fertilizer and pesticide for planting.]

“Mapagtapos (ng pag-aaral) mga anak ko at matulungan pa mga kapatid ko.” 

[To make my children graduate (from school) and help my siblings more.]

Contemplating on these answers, it is quite evident that farmers desire simple yet impactful things. Amidst the countless criticisms and suggestions from politicians, academicians, and even citizens in order to improve the country’s agricultural sector and the farmers’ way of living—the answer seems so light and easy in the eyes of these hardworking people. They simply need and want a better quality of life for themselves, for their families, and if possible, for the whole nation. 

Receiving enough funding and support from the government, legally acquiring the land originally deserved, selling hard-earned products at a just and reasonable price, and experiencing a more proper and formal education—these are only some of the many other aspirations in life that most unprivileged Filipino farmers yearn for every single day. 

Ironically enough, the persons who have the capability to make these dreams a reality are the very ones who are causing the farmers’ adversity. 


Agriculture. (n.d.). Retrieved from
Domingo, L. (2016). Official backs IPs 'kaingin' system. Retrieved from
Filipino farmers- a dying breed? (2013). Retrieved from
Habito, C. (2018). Our lowly farmworkers. Retrieved from
Inorganic Fertilizer: Advantages and Disadvantages. (2019). Retrieved from
Pesticide classifications and formulations. (n.d.). Retrieved from
Philippines-Agriculture. (n.d.). Retrieved from

This article was submitted by the author as a class requirement in AgSci 11, Dept of Agronomy, VSU

Sunday, January 10, 2021

Where have all the students gone?

In March 2020 last year, because of the worsening Covid-19 pandemic, the Philippine education officials suspended the classes in all schools, and students were advised to go home. Suddenly, the normally vibrant university and college campuses have turned into empty and lonely places. At the Visayas State University in Baybay City, Leyte, where more than half of the university student population reside in dormitories inside the campus, the impact of the indefinite suspension of classes has been dramatic. The campus appears desolate. The only positive effect of the pandemic is the regeneration of the natural environment. One wonders where the students have gone, and when they are coming back. Below are some photos of some parts of the 100-hectare campus that I have taken during this pandemic:

This is the main street in the lower campus after entering the gate. On normal days, traffic is heavy here.

This is the old Palomaria street that goes straight to the beach, a normally busy street before 
the pandemic.

The street near the guest house, apartelle, and pavilion where tourists can be seen strolling.

The normally very busy intersection near the Ecopark, Agronomy and Soil Science, 
College of Management and Economics, and University Library.

The street leading to the Cocofed dormitories. Before the suspension of classes, 
students filled this street even during evenings and weekends.

The VSU beach along the Camotes Sea. On a fine day before the pandemic, the beach 
was the favorite hangout for students and tourists.

The VSU beach resort. Before the pandemic, the resort was always fully booked for weddings, 
birthdays, reunions, and conferences.

Saturday, January 18, 2020

The best research universities in the Philippines in 2020

The best research universities in the Philippines are the University of the Philippines Diliman, University of the Philippines Manila, University of the Philippines Los Banos, De La Salle University, University of Santo Tomas, Ateneo de Manila University, University of the Philippines Visayas, Mindanao State University-Iligan Institute of Technology, University of San Carlos, Visayas State University, Silliman University, and Central Luzon State University.

The University of the Philippines Diliman is the country's best research university
(Photo source:

Except Silliman University, all 11 universities are members of the prestigious National Science Consortium of the Department of Science and Technology-Science Education Institute implementing the Accelerated Science and Technology Human Resource Development Program (ASTHRDP) graduate scholarships.

The ranking is based on the total number of publications and total ResearchGate Score (or RG Score) of each university extracted from ResearchGate this January 2020. The number of publications refers to the publications of ResearchGate members from each university while the RG Score is based on the research outcome appearing in the researchers’ profile and their interactions with other members and the reputation of their peers.

As can be seen from the table, the ranking changes especially in the lower 6 to 12 positions when it is based on the RG Score instead of total publications. It can be argued that the total publication is a more reliable basis of ranking the universities than the RG Score because of the lack of transparency on how the score is calculated. There are of course scientists who prefer to use the RG Score because it indicates the researchers’ impact.

ResearchGate is the world’s largest and most popular scholarly network with over 15 million members and access to more than 130 million publications.

Note: This is a ranking based on the research data (publications and RG score) for the Philippine universities that are available and easily accessible at ResearchGate. The author gathered the data and made the ranking. ResearchGate does not make rankings of institutions or scientists.--VBA 

Saturday, January 4, 2020

Research without borders: Humboldt Conference 2019, Bangkok, Thailand

The First Southeast Asian Humboldt Kolleg (Conference) organized by the Humboldt Clubs (or Associations) of Indonesia, Malaysia, Philippines, Thailand and Vietnam and hosted by the Humboldt Club of Thailand led by its president, Prof. Wanchai De-Eknamkul, was held on 19-21 December 2019 at Chulalongkorn University, Bangkok, Thailand.

With the theme “Southeast Asian Research Without Borders”, the scientific conference was part of the global celebrations honoring the 250th birth anniversary of Alexander von Humboldt, one of the greatest and most celebrated scientists of the 19th century. It was funded by the Alexander von Humboldt Foundation and the National Research Council of Thailand.

Humboldt fellows from Indonesia, Malaysia, Philippines, Thailand and Vietnam as well as some guests from
SE Asia and Germany 

Humboldtians are outstanding scientists who have been awarded the world-renowned Humboldt Research Fellowships (and Humboldt Research Awards for the few world-leading scientists) by the Alexander von Humboldt Foundation based in Bonn, Germany. Selections for the fellowships are highly competitive. 
“There are no quotas, neither for individual countries nor for particular academic disciplines. Only the excellent scientific performance of the applicant counts” ( Fellows receive support from the Foundation for life. Until now only 30 scientists in the Philippines have received the prestigious Humboldt fellowship.

Nine (9) Filipino Humboldtians attended the Bangkok conference. They were Dr. Christopher C. Bernido and Dr. Maria Victoria Bernido (University of San Carlos in Cebu City/Research Center for Theoretical Physics, Bohol), Dr. Rafael Espiritu (De la Salle University), Dr. Arnold Hallare (U.P. Manila), Dr. Maribel Dionisio-Sese (U.P. Los Banos), Dr. Allan Patrick Macabeo (University of Santo Tomas), Dr. Ian Navarrete (Ateneo de Manila University) and Dr. Victor B. Asio and Dr. Erlinda Vasquez (Visayas State University).

The Philippine delegation (L-R): Dr. Hallare, Dr. C. Bernido, Dr. M. Bernido, Dr Sese, Dr. Vasquez, Dr. V. Asio,
Dr. Navarrete, Dr. Espiritu, Dr. L. Asio and Dr. Macabeo 

Dr. Chris Bernido (Ramon Magsaysay Awardee in 2010) was one of the four Outstanding Humboldtians from SE Asia who were recognized during the conference. Dr. Asio, the president of Humboldt Club Philippines, presented a paper on the status of the Humboldt Club in the Philippines and served as a plenary session moderator. All the other Filipino Humboldtians gave oral presentations on topics in their field of research.

The conference organizers invited a few non-Humboldtian researchers from the five countries as well as professors from Germany who served as plenary speakers. Dr. Luz G. Asio from the Department of Agronomy at Visayas State University, was the sole non-Humboldtian participant from the Philippines.

The Alexander von Humboldt Foundation was established by the government of the Federal Republic of Germany to promote international academic cooperation between excellent scientists and scholars from Germany and from abroad. It is funded by the Federal Foreign Office, the Federal Ministry of Education and Research, the Federal Ministry for Economic Cooperation and Development as well as other national and international partners.

Werner Heisenberg, one of the greatest physicists of the 20th century (Nobel Prize for Physics 1932 for the creation of quantum mechanics), was the first president of the Foundation after its re-establishment in 1953 until 1975. Feodor Lynen (Nobel Prize for Medicine 1964) and Wolfgang Paul (Nobel Prize for Physics 1989) also served as presidents of the Foundation from 1975-79 and 1979-89, respectively.

The Foundation maintains a global network of more than 29,000 Humboldtians from all disciplines in over 140 countries worldwide including 55 Nobel Laureates.

Thursday, December 5, 2019

Happy World Soil Day 2019


The faculty, staff and students of the Department of Soil Science (Head: Dr. Suzette B. Lina), College of Agriculture and Food Science of Visayas State University (VSU) in Leyte, Philippines, join the rest of the world in celebrating the World Soil Day (WSD) on December 5, 2019. A seminar and a quiz contest among students are part of the celebration at VSU. 

December 5 of every year was chosen for this important celebration in honor of  the late H.M. King Bhumibol Adulyadej, King of Thailand whose birthday was December 5. King Bhumibol was one of the main proponents of this initiative. The proposal for the establishment of WSD was made by the International Union of Soil Sciences (IUSS) in 2002.

The Food and Agriculture Organization (FAO) of the United Nations supported its formal establishment as a global awareness-raising platform. In December 2013, the UN General Assembly at the 68th session declared 5 December as World Soil Day. The theme of WSD 2019 is “Stop Soil Erosion, Save our Future”.

There are hundreds of events around the world to celebrate WSD 2019 according to the online map prepared by FAO. In the Philippines, only VSU and Don Mariano Marcos State University (DMMSU) in La Union have organized such events.